Ultimately, you'll have to tweak ratios to fit your own body chemistry (no two people are the same, unfortunately), but I have had the best luck on around 20-30% carb, 20-30% protein, 50% fat. Might sound counterintuitive, but I try to minimize carbs instead of fat. Reasoning is that at least for me, eating fat serves as kind of a fuse to light up all the fat that's sitting around my body. Carbs just interfere with that process.

The reason for the variation above is that it's hard to peg down exact ratios without getting monotonous with food choices.